Civil Services Prep

Prelims 2012 · Science and Technology · Question 13

What is the role of ultraviolet (UV) radiation in the water purification systems?<br/>1. It inactivates/kills the harmful microorganisms in water.<br/>2. It removes all the undesirable odours from the water.<br/>3. It quickens the sedimentation of solid particles, removes turbidity and improves the clarity of water.<br/><br/>Which of the statements given above is/are correct?

  1. 1 only
  2. 2 and 3 only
  3. 1 and 3 only
  4. 1, 2 and 3

Answer

1 only

1. Correct. UV radiation is used for disinfection; it damages the DNA/RNA of bacteria, viruses and other pathogens, thereby inactivating them.

2. Incorrect. UV treatment does not remove odours; odour removal usually needs activated carbon, aeration, oxidation, etc.

3. Incorrect. UV does not aid sedimentation or remove turbidity; suspended particles are handled by coagulation, sedimentation and filtration. In fact, high turbidity can reduce UV effectiveness.

Therefore, only statement 1 is correct.

  1. Which of the following statements with regard to genetic medicine is/are correct ? 1. Genetic medicines…
  2. Which of the following statements with regard to Large Language Models (LLMs) used in machine learning is/are…
  3. Which of the following statements with regard to stealth technology is/are correct ? 1. Stealth objects have a…
  4. Which of the following statements with regard to Black Boxes used in modern aircrafts is/are correct ? 1. They…
  5. Consider the following statements with regard to involvement of private entities in India's space programme :…
  6. Which of the following statements with regard to drone swarms is/are correct ? 1. They use Terahertz band of…